The bus leaves from Cancun City bus terminal at 22:15 hours. I think the fare is up around 500 pesos now.

Another option is to get one of the half-hourly ADO Riviera airport shuttle buses from the airport to Playa del Carmen (156 pesos). Playa might be a better place to kill time if you have a lot of time to kill. You have to be aware that PdC has two bus terminals -- the airport shuttle bus arrives at the bus terminal on 5th Ave. and the overnight bus departs at 23:40 hours from the other terminal (Alterna) on 20th Ave. at 12th Street. The fare is a bit less from PdC.

When you arrive at the 5th Ave terminal, there is a luggage storage area up the stairs -- small fee. If not too heavy, you can walk to the other terminal. A taxi from the bus terminal is 50 pesos, but if you walk down the block and wave one down, the fare should be 30 pesos.